A spate of fuel thefts have taken place in Cornwall with one victim predicting the problem is "going to get worse" with rising fuel costs.
The thefts took place on Wednesday overnight with hundreds of pounds of diesel siphoned out of haulage and coach vehicles.
John Keam from Probus, who runs JK Coaches, said he had £200 worth of the fuel taken from his 53-seat executive coach while it was parked at a garage in Indian Queens overnight on Wednesday.
The same night, fuel thieves hit pallet distributor Kay Transport on Grampound Road, taking 600 litres of diesel from six vehicles, so badly damaging one it has been declared off road since.
Mr Keam, who runs the company to supplement his income as an electrician, said: "On the previous Saturday we did an airport shuttle from Exeter to Penzance and all of this has eaten in to our profits.
"It's going to get worse, there's no deterrent."
Mark Adams, the manager of Kay Transport, which has its headquarters in Plymouth, said the thefts would have happened between 10pm and 5.30am the next morning.
He said the compound they were kept in was well lit with security cameras and covered by CCTV.
He said: "We came into work in the morning and found that six vehicles had had their fuel tanks tampered with. It would have taken someone pretty well geared up.
"Somebody can't just turn up and take 600 litres of fuel without being well equipped."
Last year, the police warned farmers and HGV drivers in the Westcountry to be on their guard after several diesel thefts from vehicles.
Police urged drivers to park HGVs with fuel tanks facing a CCTV camera, in a well-lit area or so that their fuel tanks are inaccessible to offenders.
They should not park HGVs too close to one another, to prevent possible hiding places for offenders and if possible, should park in secure yards.
Farmers or firms should avoid putting diesel storage tanks in isolated areas, or consider fencing/planting to disguise a tank. A mobile bowser can be kept in a secure barn.
Police advise locking fuel tanks if possible, not leaving empty containers nearby, and using diesel dye to make it more easily identifiable
A Devon and Cornwall Police spokesman said: "If anyone sees anything suspicious don't hesitate to contact the police."